dccp: constify dccp_make_response() socket argument
Like tcp_make_synack() the only time we might change the socket is
when calling sock_wmalloc(), which is using atomic operation to
update sk->sk_wmem_alloc
Also use MAX_DCCP_HEADER as both IPv4/IPv6 use this value for max_header.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index bebc735..31e96df 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -293,7 +293,7 @@
void dccp_destroy_sock(struct sock *sk);
void dccp_close(struct sock *sk, long timeout);
-struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
+struct sk_buff *dccp_make_response(const struct sock *sk, struct dst_entry *dst,
struct request_sock *req);
int dccp_connect(struct sock *sk);
diff --git a/net/dccp/output.c b/net/dccp/output.c
index 0248e8a..4ce912e 100644
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -390,7 +390,7 @@
return dccp_transmit_skb(sk, skb_clone(sk->sk_send_head, GFP_ATOMIC));
}
-struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
+struct sk_buff *dccp_make_response(const struct sock *sk, struct dst_entry *dst,
struct request_sock *req)
{
struct dccp_hdr *dh;
@@ -398,13 +398,18 @@
const u32 dccp_header_size = sizeof(struct dccp_hdr) +
sizeof(struct dccp_hdr_ext) +
sizeof(struct dccp_hdr_response);
- struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
- GFP_ATOMIC);
- if (skb == NULL)
+ struct sk_buff *skb;
+
+ /* sk is marked const to clearly express we dont hold socket lock.
+ * sock_wmalloc() will atomically change sk->sk_wmem_alloc,
+ * it is safe to promote sk to non const.
+ */
+ skb = sock_wmalloc((struct sock *)sk, MAX_DCCP_HEADER, 1,
+ GFP_ATOMIC);
+ if (!skb)
return NULL;
- /* Reserve space for headers. */
- skb_reserve(skb, sk->sk_prot->max_header);
+ skb_reserve(skb, MAX_DCCP_HEADER);
skb_dst_set(skb, dst_clone(dst));